Reducing resolution......

Ok, so this might be a dumb question, but in testing my K-3, it just got me to wonder - are there any benefits, besides reducing the file size, of reducing the image mp on a camera?

The K-3 allows you to shoot 24mp, but also 14mp, 6mp, and 2mp. I was just curious, is there anyone out there who shoots at a lower resolution than the max for your camera, and what are the benefits that drive you to do so? Does this alter the noise you see?